Oops, it doesn't look like 'Dress Like A Muggle day' is a national day..

Other days

Appreciate Yaself A Lil Extra Day

My Little Pony Day

Lisp Day

Carpenters Day

Prosecco Day

Stud Day

Self Appreciation Day

Tell A Fairytale Day

Nae Nae Day

African Immigrant And Refugee Hiv And Hep Awareness Day